In this file:


·         Bulgaria declares state of emergency as disease spreads

·         EU Spokeswoman Urges Action to Save Bulgarian Pork Industry

·         Can pigs become infected with ASF by eating flies?



Bulgaria declares state of emergency as disease spreads


By Meghan Grebner, Brownfield

August 8, 2019


Bulgaria has declared a state of emergency after the country had to cull 130,000 pigs in two weeks due to the spread of African Swine Fever.  According to the Swine Health Information Center’s latest surveillance report, the disease has infected animals on backyard farms and has now also spread to 6 large commercial farms in the country.


The country’s agriculture minister says sanitary zones have been set up around all registered commercial operations and small, private pig farms and home-bred animals without biosecurity measures will not be allowed in the zones.


Last week, the first two cases of ASF in Southwestern Bulgaria were reported in wild boars...





EU Spokeswoman Urges Action to Save Bulgarian Pork Industry


Jennifer Shike, FarmJournal's Pork

August 8, 2019


A European Union Commission spokeswoman said the spread of African swine fever (ASF) in Bulgaria “is worrying” and urged action against this catastrophic disease on Thursday.


Bulgaria is one of the EU’s poorest states and has reported more than 30 outbreaks of the disease to date, resulting in around 130,000 culled pigs so far, Reuters reports. Experts fear Bulgaria could lose its entire 600,000 pig breeding industry to this devastating virus.


Bulgarian industry officials fear the outbreak could cause damages of up to $1.15 billion.


The EU's head of health and food safety, Vytenis Andriukaitis, offered EU support to Bulgaria after meeting with the country's agriculture minister Desislava Taneva on Tuesday. Taneva said Bulgaria will receive $3.25 million in EU financial aid to help fight the disease...





Can pigs become infected with ASF by eating flies?

At present the only blood-feeding insect demonstrated to be a vector of African swine fever is the stable fly, which can maintain high levels of virus for 2-3 days.


Ann Hess, National Hog Farmer

Aug 09, 2019


A 2018 study entitled, “Infection of pigs with African swine fever virus via ingestion of stable flies” is making the rounds again as several industry experts try to make sense of the unexpected spread of African swine fever to farms in Eastern Europe with relatively decent biosecurity.


To investigate this possibility further, Danish researchers allowed pigs to ingest flies that had fed on ASFVspiked blood, which had a realistic titer for an infected pig. Some of the pigs became infected with the virus.


While it’s unlikely that ingestion of ASF-infected flies is a common route for transmission, the scientists say the results indicate that Stomoxys flies could be one possible route of transmission over short distances (e.g., within farms), while larger flies, such as the Tabanidae, might explain some longer distance examples of ASFV transmission (e.g., into and between farms). The researchers concluded that bloodfeeding flies could be a route for the observed, but unexplained, introduction of ASFV into farms with high biosecurity.


We know that ASF can be transmitted to pigs through feeding of food waste containing contaminated pork products as well as direct contact with infected pigs, their waste, blood, contaminated clothing, feed, equipment and vehicles, and in some cases, ticks. But we really haven’t talked about flies yet.


According to Peter Fernandez, a former Animal and Plant Health Inspection Service veterinarian, at present the only blood-feeding insect demonstrated to be a vector of ASF is the stable fly (Stomoxys calcitrans), which can maintain high levels of virus for 2-3 days and inject or transmit the virus to pigs up to 24 hours after virus ingestion.


“In experiments with purposefully infected stable flies, pigs that ate flies could also become infected,” Fernandez says. “Both of these are examples of mechanical transmission.”


The infectious disease epidemiologist says a number of experiments have attempted to investigate the possibility of other insects as competent vectors for ASF such as: hard ticks, blow fly larvae, lice, mosquitoes and mites.  However, all provided little or no evidence of effective transmission.


“ASF virus is known to be transmitted by soft ticks of the genus Ornithodoros both in a natural sylvatic cycle among African warthogs and Ornithodoros moubata and also in domestic swine and Ornithodoros erraticus in the Iberian Peninsula,” Fernandez says. “This is the only known biological vector of ASF, which means the virus actually replicates in pigs and also in soft ticks.  All other transmission mentioned is mechanical transmission which means there is no replication in the insect vector and the insect acts as a small ‘flying syringe.’”


While the mechanical transmission by flies seems pretty low on the totem pole in terms of transmission, future studies on the role of blood-feeding flies may be warranted...


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